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From: Sven Schnelle <svens@stackframe.org>
To: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Subject: Re: [PATCH 2/2] parisc: add support for TOC (transfer of control)
Date: Sun, 10 Oct 2021 13:42:01 +0200	[thread overview]
Message-ID: <87pmsdgl86.fsf@x1.stackframe.org> (raw)
In-Reply-To: <d2fd6be4-c76e-6be4-924f-484549883aa0@gmx.de> (Helge Deller's message of "Sun, 10 Oct 2021 11:13:25 +0200")

Helge Deller <deller@gmx.de> writes:

> On 10/9/21 23:38, Sven Schnelle wrote:
>> +	load32	PA(toc_stack),sp
>> +	/*
>> +	 * deposit CPU number into stack address,
>> +	 * so every CPU will have its own stack.
>> +	 */
>> +	depw	%r4,18,2,%sp
>
> Shouldn't this be 5 instead of 2, otherwise it limits it to 4 CPUs,
> while we currently can have up to 32 (see arch/parisc/Kconfig).
> e.g.:	depw	%r4,18,5,%sp
>
>> +
>> ...
>> +SYM_DATA(toc_handler_size, .long . - toc_handler)
>> +SYM_DATA(toc_lock, .long 1)
>> +
>> +	__PAGE_ALIGNED_BSS
>> +	.align 16384*NR_CPUS
>
> ^ This align is too big, esp. since NR_CPUS can be 32.
> At minimum a stack needs to be 64-byte aligned.
> I think a simple .align 64 here, and changing the multiplication
> above with adding the offset is better.

The .align was a quick way to test the stack offset, but i agree that
doing a regular add is the better way. Also i missed to align toc_lock
at a 16 byte boundary.

  reply	other threads:[~2021-10-10 11:42 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-09 21:38 [PATCH 0/2] add TOC support Sven Schnelle
2021-10-09 21:38 ` [PATCH 1/2] parisc/firmware: add functions to retrieve TOC data Sven Schnelle
2021-10-09 21:38 ` [PATCH 2/2] parisc: add support for TOC (transfer of control) Sven Schnelle
2021-10-10  9:13   ` Helge Deller
2021-10-10 11:42     ` Sven Schnelle [this message]
  -- strict thread matches above, loose matches on Subject: below --
2021-10-10 18:38 [PATCH v2 0/2] add TOC support Sven Schnelle
2021-10-10 18:38 ` [PATCH 2/2] parisc: add support for TOC (transfer of control) Sven Schnelle
2021-10-10 19:31   ` Helge Deller
2021-10-10 19:36     ` Sven Schnelle
2021-10-12 10:03       ` Helge Deller
2021-10-15 16:22   ` Rolf Eike Beer

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